This study investigates the anodizing of 6061 aluminum alloy using an alkaline solution composed of sodium hydroxide (NaOH), sodium tetraborate (Na2B4O7) and potassium pyrophosphate (K4P2O7). The effects of the electrolyte compositions as well as temperature and voltage on the growth and microstructure of anodic films were investigated. Results showed that all these parameters have effects on the current density of the anodizing process and thickness of the anodic films. The current density increases with process parameters except for Na2B4O7, while as the process parameters increase, the anodic film thickness initially increases and then decreases. The morphology of the anodic film is notably affected by variables NaOH, Na2B4O7, temperature, and voltage. Increasing NaOH concentration and temperature resulted in a decrease in surface uniformity, while Na2B4O7 exhibited an opposite effect. Voltage significantly affected the diameter of the anodic film's pores, resulting in larger pores at higher voltages, which leading to poorer dyeing effect for the anodized samples.
LiJWeiHZhaoK, et al.Effect of anodizing temperature and organic acid addition on the structure and corrosion resistance of anodic aluminum oxide films. Thin Solid Films2020; 713: 138359.
2.
LeeWHanHLotnykA, et al.Individually addressable epitaxial ferroelectric nanocapacitor arrays with near Tb inch−2 density. Nat Nanotechnol2008; 3: 402–407.
3.
WangHLiGLiuW. Effect of laminar flow on the barrier properties of coatings. J Appl Polym Sci2017; 134: 45581.
4.
ZhangYLiGLiuW. Effect of coating thickness on the corrosion resistance of epoxy coatings under alternating pressure. Corros Sci2019; 149: 239–248.
5.
XuJLiGLiuW. Influence of substrate surface pretreatment on the adhesion of epoxy coatings. J Coat Technol Res2021; 18: 251–260.
6.
MishraPHebertKR. Self-Organization of anodic aluminum oxide layers by a flow mechanism. Electrochim Acta2020; 340: 135879.
7.
KorzekwaJ. Modification of the structure and properties of oxide layers on aluminium alloys: a review. Rev Adv Mater Sci2023; 62: 20230108.
8.
MiaoXShiXShenY, et al.Investigation of hexamethylenetetramine effects on formation and corrosion resistance of anodic coatings developed on AZ31B alloys. Surf Coat Technol2022; 447: 128824.
9.
ChungPPWangJDurandetY. Deposition processes and properties of coatings on steel fasteners—a review. Friction2019; 7: 389–416.
10.
BoudairaRMeglaliOBouraiouA, et al.Optimization of sulphurization temperature for the production of single-phase CZTS kesterite layers synthesized by electrodeposition. Surf Eng2020; 36: 1000–1011.
11.
MuralirajaRSelvanRASSelvakumarA, et al.A review of electroless coatings on non-metals: bath conditions, properties and applications. J Alloy Compd2023; 960: 170723.
12.
ZhengQChenTLiH. Enhanced mechanical properties of molybdenum-coated aluminium via laser cladding. Surf Eng2023; 39: 56–64.
13.
WangHLiGLiuW. Effect of laminar flow on the barrier properties of coatings. J Appl Polym Sci2017; 134: 45581.
14.
LiYZhangYLiuW. Effect of alternating pressure on the corrosion resistance of polyurethane coatings. J Appl Polym Sci2022; 140: 49808.
15.
OmotehinseISAbioyeTEAnasyidaA, et al.Review of parametric strategies for enhancing the mechanical and wear properties of friction stir processed aluminium alloys composites. Trans Indian Inst Met2023; 76: 2009–2031.
JohnSBalasubramanianVShenoiBA. Studies on anodizing of aluminium in alkaline electrolyte using alternating current. Surf Technol1985; 26: 207–216.
18.
PakesAThompsonGESkeldonP, et al.Anodizing of aluminium in borax solution. Trans IMF1999; 77: 171–177.
19.
KikuchiTKunimotoKIkedaH, et al.Fabrication of anodic porous alumina via galvanostatic anodizing in alkaline sodium tetraborate solution and their morphology. Electroanal Chem2019; 846: 113152.
20.
KikuchiTSatoMIwaiM, et al.Formation of bright white plasma electrolytic oxidation films with a uniform maze-like structure by anodizing aluminum in ammonium tetraborate solutions. J Electrochem Soc2022; 169: 043505.
21.
Garcia-VergaraSJSkeldonPThompsonGE, et al.Formation of porous anodic alumina in alkaline borate electrolyte. Thin Solid Films2007; 515: 5418–5423.
22.
IwaiMKikuchiTSuzukiRO. Initial structural changes of porous alumina film via high-resolution microscopy observations. ECS J Solid State Sci Technol2020; 9: 044004.
23.
IwaiMKikuchiTSuzukiRO. Self-Ordered nanospike porous alumina fabricated under a new regime by an anodizing process in alkaline media. Sci Rep2021; 11: 7240.
24.
IwaiMKikuchiT. Fabrication of unique porous alumina films with extremely high porosity and an ultra-flat barrier layer by anodizing aluminum in sodium metaborate. Electrochim Acta2021; 399: 139440.
25.
TerashimaAIwaiMKikuchiT. Nanomorphological changes of anodic aluminum oxide fabricated by anodizing in various phosphate solutions over a wide pH range. Appl Surf Sci2022; 605: 154687.
26.
OnoSAsohH. A new perspective on pore growth in anodic alumina films. Electrochem Commun2021; 124: 106972.
27.
LiCNiYGongJ, et al.A review: research progress on the formation mechanism of porous anodic oxides. Nanoscale Adv2022; 4: 322–333.
28.
IkedaHIwaiMNakajimaD, et al.Nanostructural characterization of ordered gold particle arrays fabricated via aluminum anodizing, sputter coating, and dewetting. Appl Surf Sci2019; 465: 747–753.
29.
BelwalkarAGrasingEVangeertruydenW, et al.Effect of processing parameters on pore structure and thickness of anodic aluminum oxide (AAO) tubular membranes. J Membr Sci2008; 319: 192–198.
30.
KlimasVNaujokaitisAJankauskasS, et al.Anodising of aluminium in formate solutions with formation of porous alumina arrays. Trans IMF2022; 100: 333–341.
31.
YangXZYangXYamamuraK. Effects of electrolyte type and concentration on the anodic oxidation of 4H-SiC (0001) in slurryless electrochemical mechanical polishing. Electrochim Acta2024; 474: 143531.
32.
TheohariSKontogeorgouC. Effect of temperature on the anodizing process of aluminum alloy AA 5052. Appl Surf Sci2013; 284: 611–618.
33.
AertsTDe GraeveITerrynH. Anodizing of aluminium under applied electrode temperature: process evaluation and elimination of burning at high current densities. Surf Coat Technol2010; 204: 2754–2760.
34.
OnoS. Nanostructure analysis of anodic films formed on aluminum-focusing on the effects of electric field strength and electrolyte anions. Molecules2021; 26: 7270.
35.
ParkISLeeMHBaeTS, et al.Effects of anodic oxidation parameters on a modified titanium surface. J Biomed Mater Res2008; 84B: 422–429.
BaeSHCholISonI. Effects of the process conditions on the color of dye-treated anodized AA5052. J Nanosci Nanotechnol2019; 19: 4097–4102.
38.
AertsTDimogerontakisTDe GraeveI, et al.Influence of the anodizing temperature on the porosity and the mechanical properties of the porous anodic oxide film. Surf Coat Technol2007; 201: 7310–7317.
39.
IwaiMKikuchiTSuzukiRO, et al.Electrochemical and morphological characterization of porous alumina formed by galvanostatic anodizing in etidronic acid. Electrochim Acta2019; 320: 134606.
